Carcharhiniformes, the ground sharks, are the largest order of sharks, with over 270 species. They include a number of common types, such as catsharks, swellsharks, and the sandbar shark.
Scyliorhinus is a genus of catsharks in the family Scyliorhinidae. This genus is known in the fossil records from the Cretaceous period, late Albian age to the Pliocene epoch.
Requiem sharks are sharks of the family Carcharhinidae in the order Carcharhiniformes. They are migratory, live-bearing sharks of warm seas and include such species as the bull shark, lemon shark, spinner shark, blacknose shark, blacktip shark, grey reef shark, blacktip reef shark, silky shark, dusky shark, blue shark, copper shark, oceanic whitetip shark, and whitetip reef shark.
The Hexanchiformes are a primitive order of sharks, that numbering just seven extant species in two families. Fossil sharks that were apparently very similar to modern sevengill species are known from Jurassic specimens.
Chlamydoselachidae is a family of primitive deep-sea sharks in the order Hexanchiformes. They are one of only two extant families in the order alongside the cow sharks in the family Hexanchidae, and the only members of the suborder Chlamydoselachoidei.
The Lamniformes are an order of sharks commonly known as mackerel sharks. It includes some of the most familiar species of sharks, such as the great white, as well as more unusual representatives, such as the goblin shark and megamouth shark.
Cow sharks are a shark family, the Hexanchidae, characterized by an additional pair or pairs of gill slits. Its 37 species are placed within the 10 genera: Gladioserratus, Heptranchias, Hexanchus, Notidanodon, Notorynchus, Pachyhexanchus, Paraheptranchias, Pseudonotidanus, Welcommia, and Weltonia.
Chlamydoselachus is a genus of sharks and the sole extant member of the family Chlamydoselachidae, in the order Hexanchiformes. It contains two extant and four extinct species. The most widely known species still surviving is the frilled shark. It is known as a living fossil, along with Chlamydoselachus africana, also known as the southern African frilled shark, which is only found along coastal areas of South Africa. The only two extant species of this genus are deep-sea creatures which are typically weakened in areas closer to the surface. While the two extant species are similar in external appearance, they differ internally.
Paraorthacodus is an extinct genus of cartilaginous fish. It a member of the family Paraorthacodontidae, which is either placed in Hexanchiformes or in Synechodontiformes. It is known from 11 species spanning from the Early Jurassic to the Eocene. Full body fossils from the Late Jurassic of Germany suggest that juveniles had a robust body with a round head, while adults had large body sizes with tapered bodies. There was only a single dorsal fin towards the back of the body without a fin spine. The dentition had teeth with a single large central cusp along with shorter lateral cusplets, which where designed for clutching.
Gladioserratus is an extinct genus of cow shark. It contains three species:
Meristodonoides is an extinct genus of hybodont. The type species is M. rajkovichi, which was originally a species in the genus Hybodus. The species, along with other Hybodus species such as H. butleri and H. montanensis, was reassigned to Meristodonoides by Charlie J. Underwood and Stephen L. Cumbaa in 2010. The species is primarily known from remains from the Cretaceous of North America, spanning from the Aptian/Albian to Maastrichtian, making it one of the last surviving hybodont genera, though records of the genus likely extend back as far as the Late Jurassic, based on an undescribed skeleton from the Tithonian of England, and fragmentary teeth from the Kimmeridgian of Poland, England and Switzerland. Other remains of the genus are known from the Coniacian of England, the Aptian-Albian of France, and the Campanian of European Russia. The morphology of the teeth suggests an adaptation to tearing prey. Fossils from the Western Interior Seaway suggest that it preferred nearshore marine environments, being absent from deeper-water areas, with it likely also being able to tolerate brackish and freshwater conditions.
Mcmurdodus is an extinct genus of chondrichthyan from Antarctica and Australia and the sole member of the family Mcmurdodontidae. It contains two extinct species. However, the Australian species M. whitei has been found to be different from the Antarctic type species M. featherensis, and thus M. whitei has been classified into a new genus, Maiseyodus.
Synechodontiformes is an extinct order of prehistoric shark-like cartilaginous fish, known from the Permian to the Paleogene. They are considered to be members of Neoselachii, the group that contains modern sharks and rays.
Paracestracion is an extinct genus of heterodontiform sharks from Early Jurassic to Early Cretaceous-aged rocks of England, France, Germany and Luxembourg. The genu was first described in 1911 by Ernst Hermann Friedrich von Koken in Karl Alfred von Zittel.
Notidanodon is an extinct genus of cow shark. Fossils ascribed to this genus are known from the Jurassic and Cretaceous periods. Recently, the genus underwent a major revision and was split into two after the erection of Xampylodon to accommodate the species X. dentatus, X. loozi, and X. brotzeni. The genus is now known only from New Zealand, Antarctica, Africa, and South America.
Archaeogaleus is an extinct genus of requiem shark from the Cretaceous period. It is known only from the species A. lengadocensis. It was described from the Valanginian stage of France. The specific epithet refers to Lengadòc, the region where Occitan was historically spoken. It is the oldest known requiem shark and has a presumed dentition similar to the modern form Scoliodon.
Antrigoulia is an extinct genus of palaeospinacid shark from the Cretaceous period. It is named after a farm in the vicinity of the type locality called Mas d’Antrigoule. It is known from a single species consisting of isolated teeth from the Valanginian of France, A. circumplicata. The name is derived from the concentric folds on the labial side of its teeth.
Ctenacanthiformes is an extinct order of elasmobranch fish. They possessed ornamented fin spines at the front of their dorsal fins and cladodont-type dentition, that is typically of a grasping morphology, though some taxa developed cutting and gouging tooth morphologies. Some ctenacanths are thought to have reached sizes comparable to the great white shark, with body lengths of up to 7 metres (23 ft) and weights of 1,500–2,500 kilograms (3,300–5,500 lb). Ctenacanths are typically thought to have existed from the Devonian to the Late Permian, becoming extinct in the Permian-Triassic extinction event. Members of the family Ctenacanthidae may have survived into the Cretaceous based on teeth found in deep water deposits of Valanginian age in France and Austria, however, other authors contend that the similarity of these teeth to Paleozoic ctenacanths is only superficial, and they likely belong to neoselachians instead. The monophyly of the group has been questioned, with some studies recovering the group as a whole as paraphyletic or polyphyletic.
Dykeius is an extinct genus of large shark in the family Chlamydoselachidae. It contains a single known species, D. garethi, from the Late Cretaceous Northumberland Formation of Canada. The genus and species names honor paleontologist Gareth J. Dyke.
Sphenodus is an extinct genus of shark. It is placed as a member of the extinct family Orthacodontidae, which is either considered to be a member of the extinct order Synechodontiformes, or the modern shark order Hexanchiformes. 29 species have been described, though some of these are likely synonyms, which span from the Early Jurassic (Sinemurian) to Paleocene (Danian). Most species are only known from isolated teeth, though the species Sphenodus macer and Sphenodus nitidus from the Late Jurassic of Germany are known from skeletons. These suggest that it was relatively large, with a body length of 2–3 metres (6.6–9.8 ft), with a fusiform body with a single dorsal fin placed posteriorly without a fin spine. The teeth of Sphenodus consist of a single long, narrow central cusp, with much smaller lateral cusplets. Species of Sphenodus are thought to have been actively swimming predators.
